The present invention relates generally to an IC card and an IC card data communication method. Especially, the present invention is applicable to non-contact type IC cards.
With an IC card of non-contact type, various data are recorded and read out by use of a dedicated reader/writer.
Referring to FIG. 6, there is shown a schematic diagram illustrating a relationship between an IC card and a reader/writer. An IC card 1 is constituted by a wiring board on which a loop antenna 2 and an integrated circuit 3 are arranged and a sheet material such as a plastic, which are laminated into a sheet. With the IC card 1, the integrated circuit 3 is operated by a high-frequency signal power induced on the loop antenna 2, thereby transferring various data with a reader/writer 5 via the loop antenna 2.
With the reader/writer 5, a loop antenna 6 is driven by a predetermined driver circuit and, when the IC card 1 turns on, a high-frequency signal is induced on its loop antenna 2, thereby starting the operation of the IC card 1. Also the reader/writer 5 is adapted to transfer commands and data with the IC card 1 by switching the driving of the loop antenna 6 by a modulation/demodulation circuit 7 and processing the high-frequency signal obtained by the loop antenna 6 under the control of a DPU (Digital Processing Unit) 8.
To be more specific, referring to FIG. 7, a signal generation circuit 9 in the reader/writer 5, generates a high-frequency signal of 13.56 MHz, for example, under the control of the DPU 8 and drives the loop antenna 6 with this signal. The DPU 8 instructs the signal generation circuit 9 to start its operation in response to a request from a host device, outputs various data to be sent to the IC card 1 to the modulation/demodulation circuit 7, and captures various data received at the modulation/demodulation circuit 7. Repeating these processes, the DPU 8 executes the processing such as mutual-authentication with the IC card 1, records data received from the host device to the IC card 1, and reads data recorded to the IC card 1 to output the data to the host device.
The modulation/demodulation circuit 7 modulates the output data of the DPU 8, varies the terminal impedance of the antenna 6 on the basis of the modulation result, and thereby sends the modulated output data to the IC card 1. Also, the modulation/demodulation circuit 7 processes the high-frequency signal at the loop antenna 6 with the terminal impedance of the loop antenna 6 kept to a constant value, thereby detecting an impedance variation at the loop antenna 2 of the IC card 1 coupled to the loop antenna 6. The modulation/demodulation circuit 7 receives the data sent from the IC card 1 and outputs the received data to the DPU 8.
In the IC card 1, the high-frequency signal induced on the loop antenna 2 is detected by a low-pass filter formed by a diode 11, a resistor 12, and a capacitor 13 incorporated in the integrated circuit 3. A power supply circuit 14 rectifies the received detected high-frequency signal and stabilizes the rectified signal to generate an operating power supply.
The modulation/demodulation circuit 15 receives the detection result via a high-pass filter formed by a capacitor 16 and a resistor 17 and processes the received detection result to demodulate the data transmitted by the reader/writer 5. Further, the modulation/demodulation circuit 15 modulates output data from a sequencer 19 under the control thereof, thereby controlling the on/off of a field-effect transistor FET on the basis of the modulation result. The on/off control causes the FET to ground load Z connected to the anode of the diode 11. Consequently, in the IC card 1, the terminal impedance of the loop antenna 2 coupled with the loop antenna 6 of the reader/writer 5 is switched, transmitting various data to the reader/writer 5.
The sequencer 19 starts operating on the power supplied from the power supply circuit 14 to output various data to the modulation/demodulation circuit 15 in accordance with the data supplied from the reader/writer 5 detected by the modulation/demodulation circuit 15. Consequently, the IC card 1 approaches the reader/writer 5 and starts operating. Detecting a polling from the reader/writer 5, the IC card 1 executes processing such as mutual-authentication. After a series of these operations, the sequencer 19 accesses a memory 20 in accordance with the data supplied from the modulation/demodulation circuit 15 to update the contents of the memory 20 and output the updated data to the modulation/demodulation circuit 15.
Consequently, the system based on the IC card 1 is available as a room access control means by storing the personal information of each user into his IC card 1 and as a credit card by recording purchase log information for example about various commercial articles to the IC card 1.
It is possible to use IC cards as entrance tickets for various event places. In this case, the purchase of an entrance ticket for an event place is recorded on the IC card by online access for example before entering the event. Therefore, the organizer of the event can easily and surely manage the entries by checking the recording of their IC cards at the entrance of the event place. This also allows the users to purchase desired entrance tickets from remote places.
However, the use of IC cards as entrance tickets requires copying a part of each IC card to another with security.
Namely, tickets which are issued in paper may be purchased in bulk for distribution. If the IC cards used as entrance tickets are purchased in bulk, it is possible that the entrance tickets purchased in bulk are recorded in one IC card. If this happens, the record in such an IC card must be copied to other IC cards to distribute the entrance tickets.
If the copying of a part of an IC card to others is performed by means of a reader/writer, unauthorized copies may take place. It is therefore necessary to perform the copying as securely as possible.
If an IC card is used as a credit card, the IC card may be periodically updated to a new one. If the IC card is updated, the information, such as a purchase log recorded to this IC card, must be all copied to a new IC card and as securely as possible.
An advantage of the present invention to provide an IC card and an IC card data communication method for securely copying the contents of one IC card to another. To be more specific, the present invention is intended to directly exchange data between IC cards by use of the coupling between the antennas of the IC cards via the antenna of a reader/writer, thereby securely copying the contents of one IC card onto another IC card.
According to one embodiment of the present invention, there is provided a data communication method for communicating data between a first IC card having a first antenna and a first memory and a second IC card having a second antenna and a second memory, wherein the first antenna is magnetically coupled with the second antenna through a device having an antenna to transmit data from the first memory to the second memory.
With this configuration, data is directly transferred between IC cards by use of the electromagnetic coupling of their antennas by use of the antenna of a reader/writer. Consequently, the contents of one IC card can be copied to another in security.
Various features and advantages of the present invention will become apparent from this description and the appended claims, taken in conjunction with the accompanying drawings in which like parts or elements are denoted by like reference symbols. The features and advantages may be desired, but not necessarily required to practice the present invention.